Means for detecting tilt in aeroplanes



W. A. McDOUGALL.

MEANS FOR DETECTING TILT IN AEROPLANES.

APPLICATION FILED DEC- 6,1918.

Patented Apr. 11, 1922.

UNlTED STATES WILLIAM ALEXANDER. MODOUGALL, OF FOREST HILL, ENGLAND.

MEANSCF'O'R. DETECTING TILT IN AEROPLANES.

Specification of Letters Patent. Patented Apr, 11, 1922 Application filed December 6, 1918.- Serial No. 265,625.

To all whom it my concern:

Be it known that I, WILLIAM ALEXANDER MCDOUGALL, of Forest Hill, in the county of London, England, a subject of the King of Great Britain and Ireland, have invented certain new and useful Improvements 1n Means for Detecting Tilt in Aeroplanes,.of

which the following is a -specification.

This invention relates to aeroplanes, hydro-aeroplanes and other like aerial craft and refers to means'for detecting when the flying machine tilts beyond a certain predeterminable angle, and for giving warning to the pilot, so that he may be rendered conscious of the tilt, and may make the neces sary corrections for restoring the machine to a horizontal position, where so desired.

The essential principle of the invention consists in providing a pendulum like device pivoted to some suitable part of the flying machine, the said device carrying an electric contact, which is adapted when the machine tilts beyond a certain angle to come against another contact, thus completing an electrical circuit through a lamp or other electrical signalling device by means of which theattention of the pilot 'is attracted, and by which he is warned of the tilt of the machine; I

In order that my invention may be more clearly understood, I will now proceed to describe the same with reference to the accompanying drawing, which shows by way of example, in a diagrammatic section, one niethod of applying the invention to an aerop ane.

Fig. 1 shows the position'of the device with the aeroplane in a horizontal position, whilst Fig. 2 shows the position of the device and its operation with the aeroplane in a tilted position.

The same letters of reference denote the same parts in boththe views.

a is a bar of wood or other suitable material, suspended between platesb, by means of a pivot b, so that it is free to swing as a pendulum. The plates b carrying the pivot are in this case mounted on one of the upper planes of the machine and 1n practice I prefer to provide two of the apparatus one mounted on each side wing of the aeroplane and to cut a slot in the wing 7, through which the top of the device passes but if it 15 not desired to interfere with the construction of the wing, f may represent anysuitable transverse horizontal member.

To the lower end of the bar a, is attached a heavy bob or weight 0.

e, e are vertical struts connected at their lower ends to a horizontal member g, such as a lower wing or plane in the case of a biplane and at their upper ends to the wing, plane or its equivalent f;-

Attached at 2' to the vertical members a, is a frame or its equivalent provided with a slot m through which the bar a passes. This slot is so arranged that it allows the pendulum to swing freely from side to side as the machine tilts around an axis'vertical to the plane of the paper, but so that it does not respond when the machine tilts around an axis at right angles to that first mentioned and substantially horizontal, that is when the machine is simply ascending and descending.

In a suitable position on the vertical bar, which position is determined according to the angle at which it is desired that the warning hereinafter mentioned shall be given is provided an electric contact stud or plated, which may be provided with an insulating and buffering means. (i is a conducting wire leading from the contact, passing up to the pivot b and from this wire passes a further conducting wire Z to an electric lamp Z. k is another contact, which may take the form of an adjustable plate and is attached to the fixed framework. From this contact plate It passes a conducting wire H, which is connected to a battery or dry cell is which is also connected to thelamp l. A

- With this arrangement, the pendulum like device will remain suspended vertically in equilibrium while the machine is flying level. When however the machine banks or tilts to one side, the pendulum remains substantially vertical but moves along the slot as the wings come into an inclined position. When the angle for which the device is. set isi'e ached, contact is made between the studs or plates or the like 03 and h and a circuit is completed through the light, calling the attention of the pilot to the tilt of the machine.

In a preferred arrangement I provide two of the pendulum like devices, one for each side and I provide two lamps of different colours, for instance red for the 'left wing amount but also whether will continue to be exhibited.

- It will be understood that the particular method of carrying out the invention may be varied within a fair interpretation of my claims.

What I claim and desire to secure by Letters Patent of the United States of America is 1. A pendulum circuit closer for use in connection with an aeroplane, hydroaeroplane or other aerial craft comprising in combination a framework, a pendulum suspended on a pivot located at the top .of said frame, a horizontal frame member beneath said pivot, and having a slot, in which said pendulum swings, said slot being arranged to guide the pendulum in its movement and to limit the amplitude of the swing of said pendulum, an insulated contact carried on said pendulum towards its free end and a second contact secured to a portion of said framework so as to co-act with the contact on said pendulum when same is swung about its pivot to a predetermined extent, for the purposes set forth.

2. A pendulum circuit closer for use in connection with an aeroplane, hydroaeroplane or other aerial craft, comprising in combination a pair of frames, located 0n each side of the plane of symmetry of the machine, a pendulum supported on a pivot located at the top of each of said frames, horizontal frame members in said frames beneath the pivots, each having a slot, in which the pendulum swings, said slots guiding the pendulums in their movement and being of such length as to limit the amplitude of the swing of said endulums, an insulated contact plate carried on the outer side of each of said pendulums, towards their free ends, and a second contact secured to a portion of each of said frames and adapted to co-act with the contact'on the pendulum adjacent thereto, for the purposes set forth.

In testimony whereof I aflix my signature in presence of two witnesses.

WILLIAM ALEXANDER McDOUGALL.

Witnesses:

A. D. VIDAL, A. BROWNE. 

